Why shouldn't I use fabric conditioner on (synthetic) fleece?

Factual Questions
1

The label of my fleece jacket says “Do not use fabric conditioner” and I was wondering why.

My wife throws fabric conditioner in with all the laundry and I was wondering if it will have done any harm. It doesn’t seem to have made any difference, but when I Googled I found a few sites saying that fabric conditioner could “impair the performance” of the fleece.

How does it do that, then?

2

I always heard that fabric softener impairs water absorption, and so you shouldn’t use it on towels. No idea about fleece, though.